470 lines
12 KiB
C
470 lines
12 KiB
C
/* Texas Instruments TMP108 SMBus temperature sensor driver
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*
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* Copyright (C) 2016 John Muir <john@jmuir.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/jiffies.h>
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#include <linux/regmap.h>
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#include <linux/slab.h>
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#define DRIVER_NAME "tmp108"
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#define TMP108_REG_TEMP 0x00
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#define TMP108_REG_CONF 0x01
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#define TMP108_REG_TLOW 0x02
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#define TMP108_REG_THIGH 0x03
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#define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */
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#define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */
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/* Configuration register bits.
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* Note: these bit definitions are byte swapped.
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*/
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#define TMP108_CONF_M0 0x0100 /* Sensor mode. */
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#define TMP108_CONF_M1 0x0200
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#define TMP108_CONF_TM 0x0400 /* Thermostat mode. */
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#define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */
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#define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */
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#define TMP108_CONF_CR0 0x2000 /* Conversion rate. */
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#define TMP108_CONF_CR1 0x4000
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#define TMP108_CONF_ID 0x8000
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#define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */
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#define TMP108_CONF_HYS1 0x0020
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#define TMP108_CONF_POL 0x0080 /* Polarity of alert. */
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/* Defaults set by the hardware upon reset. */
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#define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\
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TMP108_CONF_HYS0 | TMP108_CONF_M1)
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/* These bits are read-only. */
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#define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\
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TMP108_CONF_ID)
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#define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1)
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#define TMP108_MODE_SHUTDOWN 0x0000
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#define TMP108_MODE_ONE_SHOT TMP108_CONF_M0
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#define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */
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/* When M1 is set, M0 is ignored. */
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#define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1)
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#define TMP108_CONVRATE_0P25HZ 0x0000
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#define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */
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#define TMP108_CONVRATE_4HZ TMP108_CONF_CR1
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#define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1)
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#define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
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#define TMP108_HYSTERESIS_0C 0x0000
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#define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */
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#define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1
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#define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
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#define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */
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struct tmp108 {
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struct regmap *regmap;
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u16 orig_config;
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unsigned long ready_time;
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};
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/* convert 12-bit TMP108 register value to milliCelsius */
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static inline int tmp108_temp_reg_to_mC(s16 val)
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{
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return (val & ~0x0f) * 1000 / 256;
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}
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/* convert milliCelsius to left adjusted 12-bit TMP108 register value */
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static inline u16 tmp108_mC_to_temp_reg(int val)
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{
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return (val * 256) / 1000;
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}
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static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long *temp)
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{
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struct tmp108 *tmp108 = dev_get_drvdata(dev);
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unsigned int regval;
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int err, hyst;
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if (type == hwmon_chip) {
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if (attr == hwmon_chip_update_interval) {
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err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
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®val);
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if (err < 0)
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return err;
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switch (regval & TMP108_CONF_CONVRATE_MASK) {
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case TMP108_CONVRATE_0P25HZ:
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default:
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*temp = 4000;
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break;
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case TMP108_CONVRATE_1HZ:
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*temp = 1000;
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break;
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case TMP108_CONVRATE_4HZ:
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*temp = 250;
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break;
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case TMP108_CONVRATE_16HZ:
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*temp = 63;
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break;
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}
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return 0;
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}
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return -EOPNOTSUPP;
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}
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switch (attr) {
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case hwmon_temp_input:
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/* Is it too early to return a conversion ? */
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if (time_before(jiffies, tmp108->ready_time)) {
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dev_dbg(dev, "%s: Conversion not ready yet..\n",
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__func__);
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return -EAGAIN;
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}
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err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, ®val);
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if (err < 0)
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return err;
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*temp = tmp108_temp_reg_to_mC(regval);
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break;
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case hwmon_temp_min:
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case hwmon_temp_max:
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err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
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TMP108_REG_TLOW : TMP108_REG_THIGH, ®val);
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if (err < 0)
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return err;
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*temp = tmp108_temp_reg_to_mC(regval);
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break;
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case hwmon_temp_min_alarm:
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case hwmon_temp_max_alarm:
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err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val);
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if (err < 0)
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return err;
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*temp = !!(regval & (attr == hwmon_temp_min_alarm ?
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TMP108_CONF_FL : TMP108_CONF_FH));
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break;
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case hwmon_temp_min_hyst:
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case hwmon_temp_max_hyst:
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err = regmap_read(tmp108->regmap, TMP108_REG_CONF, ®val);
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if (err < 0)
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return err;
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switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
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case TMP108_HYSTERESIS_0C:
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default:
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hyst = 0;
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break;
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case TMP108_HYSTERESIS_1C:
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hyst = 1000;
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break;
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case TMP108_HYSTERESIS_2C:
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hyst = 2000;
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break;
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case TMP108_HYSTERESIS_4C:
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hyst = 4000;
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break;
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}
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err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
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TMP108_REG_TLOW : TMP108_REG_THIGH, ®val);
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if (err < 0)
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return err;
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*temp = tmp108_temp_reg_to_mC(regval);
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if (attr == hwmon_temp_min_hyst)
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*temp += hyst;
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else
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*temp -= hyst;
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break;
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default:
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return -EOPNOTSUPP;
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}
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return 0;
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}
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static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
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u32 attr, int channel, long temp)
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{
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struct tmp108 *tmp108 = dev_get_drvdata(dev);
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u32 regval, mask;
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int err;
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if (type == hwmon_chip) {
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if (attr == hwmon_chip_update_interval) {
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if (temp < 156)
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mask = TMP108_CONVRATE_16HZ;
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else if (temp < 625)
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mask = TMP108_CONVRATE_4HZ;
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else if (temp < 2500)
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mask = TMP108_CONVRATE_1HZ;
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else
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mask = TMP108_CONVRATE_0P25HZ;
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return regmap_update_bits(tmp108->regmap,
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TMP108_REG_CONF,
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TMP108_CONF_CONVRATE_MASK,
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mask);
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}
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return -EOPNOTSUPP;
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}
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switch (attr) {
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case hwmon_temp_min:
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case hwmon_temp_max:
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temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
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return regmap_write(tmp108->regmap,
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attr == hwmon_temp_min ?
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TMP108_REG_TLOW : TMP108_REG_THIGH,
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tmp108_mC_to_temp_reg(temp));
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case hwmon_temp_min_hyst:
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case hwmon_temp_max_hyst:
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temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
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err = regmap_read(tmp108->regmap,
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attr == hwmon_temp_min_hyst ?
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TMP108_REG_TLOW : TMP108_REG_THIGH,
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®val);
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if (err < 0)
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return err;
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if (attr == hwmon_temp_min_hyst)
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temp -= tmp108_temp_reg_to_mC(regval);
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else
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temp = tmp108_temp_reg_to_mC(regval) - temp;
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if (temp < 500)
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mask = TMP108_HYSTERESIS_0C;
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else if (temp < 1500)
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mask = TMP108_HYSTERESIS_1C;
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else if (temp < 3000)
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mask = TMP108_HYSTERESIS_2C;
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else
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mask = TMP108_HYSTERESIS_4C;
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return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
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TMP108_CONF_HYSTERESIS_MASK, mask);
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default:
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return -EOPNOTSUPP;
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}
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}
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static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
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u32 attr, int channel)
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{
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if (type == hwmon_chip && attr == hwmon_chip_update_interval)
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return 0644;
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if (type != hwmon_temp)
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return 0;
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switch (attr) {
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case hwmon_temp_input:
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case hwmon_temp_min_alarm:
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case hwmon_temp_max_alarm:
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return 0444;
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case hwmon_temp_min:
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case hwmon_temp_max:
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case hwmon_temp_min_hyst:
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case hwmon_temp_max_hyst:
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return 0644;
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default:
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return 0;
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}
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}
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static u32 tmp108_chip_config[] = {
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HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
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0
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};
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static const struct hwmon_channel_info tmp108_chip = {
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.type = hwmon_chip,
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.config = tmp108_chip_config,
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};
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static u32 tmp108_temp_config[] = {
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HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_MIN_HYST
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| HWMON_T_MAX_HYST | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
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0
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};
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static const struct hwmon_channel_info tmp108_temp = {
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.type = hwmon_temp,
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.config = tmp108_temp_config,
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};
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static const struct hwmon_channel_info *tmp108_info[] = {
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&tmp108_chip,
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&tmp108_temp,
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NULL
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};
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static const struct hwmon_ops tmp108_hwmon_ops = {
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.is_visible = tmp108_is_visible,
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.read = tmp108_read,
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.write = tmp108_write,
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};
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static const struct hwmon_chip_info tmp108_chip_info = {
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.ops = &tmp108_hwmon_ops,
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.info = tmp108_info,
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};
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static void tmp108_restore_config(void *data)
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{
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struct tmp108 *tmp108 = data;
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regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
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}
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static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
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{
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return reg != TMP108_REG_TEMP;
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}
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static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
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{
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/* Configuration register must be volatile to enable FL and FH. */
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return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
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}
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static const struct regmap_config tmp108_regmap_config = {
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.reg_bits = 8,
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.val_bits = 16,
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.max_register = TMP108_REG_THIGH,
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.writeable_reg = tmp108_is_writeable_reg,
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.volatile_reg = tmp108_is_volatile_reg,
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.val_format_endian = REGMAP_ENDIAN_BIG,
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.cache_type = REGCACHE_RBTREE,
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.use_single_rw = true,
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};
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static int tmp108_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct device *hwmon_dev;
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struct tmp108 *tmp108;
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int err;
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u32 config;
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if (!i2c_check_functionality(client->adapter,
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I2C_FUNC_SMBUS_WORD_DATA)) {
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dev_err(dev,
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"adapter doesn't support SMBus word transactions\n");
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return -ENODEV;
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}
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tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
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if (!tmp108)
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return -ENOMEM;
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dev_set_drvdata(dev, tmp108);
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tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
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if (IS_ERR(tmp108->regmap)) {
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err = PTR_ERR(tmp108->regmap);
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dev_err(dev, "regmap init failed: %d", err);
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return err;
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}
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err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
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if (err < 0) {
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dev_err(dev, "error reading config register: %d", err);
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return err;
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}
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tmp108->orig_config = config;
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/* Only continuous mode is supported. */
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config &= ~TMP108_CONF_MODE_MASK;
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config |= TMP108_MODE_CONTINUOUS;
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/* Only comparator mode is supported. */
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config &= ~TMP108_CONF_TM;
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err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
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if (err < 0) {
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dev_err(dev, "error writing config register: %d", err);
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return err;
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}
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tmp108->ready_time = jiffies;
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if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
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TMP108_MODE_SHUTDOWN)
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tmp108->ready_time +=
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msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
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err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
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if (err) {
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dev_err(dev, "add action or reset failed: %d", err);
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return err;
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}
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hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
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tmp108,
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&tmp108_chip_info,
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NULL);
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return PTR_ERR_OR_ZERO(hwmon_dev);
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}
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static int __maybe_unused tmp108_suspend(struct device *dev)
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{
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struct tmp108 *tmp108 = dev_get_drvdata(dev);
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return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
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TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
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}
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static int __maybe_unused tmp108_resume(struct device *dev)
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{
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struct tmp108 *tmp108 = dev_get_drvdata(dev);
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int err;
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err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
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TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
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tmp108->ready_time = jiffies +
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msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
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return err;
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}
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static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);
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static const struct i2c_device_id tmp108_i2c_ids[] = {
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{ "tmp108", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);
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#ifdef CONFIG_OF
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static const struct of_device_id tmp108_of_ids[] = {
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{ .compatible = "ti,tmp108", },
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{}
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};
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MODULE_DEVICE_TABLE(of, tmp108_of_ids);
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#endif
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static struct i2c_driver tmp108_driver = {
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.driver = {
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.name = DRIVER_NAME,
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.pm = &tmp108_dev_pm_ops,
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.of_match_table = of_match_ptr(tmp108_of_ids),
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},
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.probe = tmp108_probe,
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.id_table = tmp108_i2c_ids,
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};
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module_i2c_driver(tmp108_driver);
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MODULE_AUTHOR("John Muir <john@jmuir.com>");
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MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
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MODULE_LICENSE("GPL");
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